Israel J. Lambo- FA Meiosis Lab ( Gizmo) PDF

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This is not for college students mainly freshmen in Hight, to be honest, I uploaded it because I didn't want to pay for premiums. Sorry if you thought this could help. But if it does I'm glad....

Description

Name:

Israel J. Lambo

Date:

04/30/21

Student Exploration: Meiosis Lab https://www.explorelearning.com Directions: Follow the instructions to go through the simulation. Respond to the questions and prompts in the orange rectangles. Vocabulary: anaphase, chromosome, crossover, cytokinesis, diploid, DNA, dominant,

gamete, genotype, germ cell, haploid, homologous chromosomes, interphase, meiosis, metaphase, mitosis, ovum, phenotype, prophase, recessive, sister chromatid, sperm cell, telophase, zygote Prior Knowledge Questions (Do these BEFORE using the Gizmo) 1. During mitosis, a single cell divides to produce two daughter cells. What must happen in the original cell so that each of the daughter cells has a complete set of chromosomes? The chromosomes must copy all DNA of the cell before cell division. 2. During sexual reproduction, two sex cells fuse to create a fertilized cell with a complete set of chromosomes. What must be true about the number of chromosomes in each sex cell? The sex cells will have 23 the number of chromosomes as the fertilized egg. Gizmo Warm-up Meiosis is a type of cell division that results in four daughter cells with half as many chromosomes as the parent cell. These daughter cells mature into gametes or sex cells. In the Meiosis Gizmo, you will learn the steps in meiosis and experiment to produce customized sex cells and offspring. On the STEPS tab, click Male. You are looking at a germ cell, or a cell that will undergo meiosis to become gametes. 1. Read the description of the interphase at the bottom of the Gizmo. What happens to the cell at the beginning of the interphase? Chromosomes are copied during the S phase and, the cell continues to prepare for division by synthesizing proteins and further increasing in size.

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2. Click on the DNA in the nucleus of the cell. Describe what happens. After, the DNA is copied the cell grows more. Specifically the layers of the cell increase size. 3. Why is it necessary for the cell to grow and duplicate its DNA before the start of meiosis? It is necessary for the cell to grow and duplicate because when the is dividing it needs two copies of its DNA, one is kept by the parent cell and the other is passed to the daughter cell. Without it, the cells would multiple but be completely new and people would transform biologically every time mitosis happened. And if they didn’t grow, the human body would be able to develop.

Activity A: Steps in Meiosis

Get the Gizmo ready: ● Make sure the STEPS tab is selected. ● Choose the Male cell first.. Click on the DNA to copy it to proceed to prophase I.

Introduction: Unlike mitosis, which produces two identical daughter cells from one parent cell, meiosis creates four unique daughter cells with half the amount of DNA as the parent cell. Question: How does meiosis create four daughter cells from one parent cell? 1. Observe: (Prophase I) Click on the nucleus to break it down then click on the DNA to condense it into chromosomes. Drag the centrosomes to the top and bottom of the cell. A. How many chromosomes does this cell have?

4 pairs

Each chromosome consists of a pair of sister chromatids, two identical strands of DNA that formed when DNA replicated during interphase. B. On the image to the right, Draw two lines connecting the pairs of homologous chromosomes (chromosomes of similar size with a matching set of genes). Click the image to select EDIT to use the drawing tool. In the Gizmo, drag the homologous chromosomes together. Click Continue. 2. Observe: (Metaphase I and Anaphase I) - Drag the groups of homologous chromosomes to the metaphase plate, then drag spindle fibers from each of the centrosomes to the chromosomes. Click the centrosome to pull the chromosomes apart. How do the chromosomes separate in anaphase I? sister chromatids are pulled to either end of the cell.

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3. Compare: An image of the anaphase step in mitosis is shown to the right. A. How does anaphase I in meiosis differ from anaphase in mitosis?

mitosis breaks the chromatids into and then meiosis pulls 2 chromatids apart.

B. At the end of anaphase I (meiosis), how many chromosomes are on each side?

2

4. Observe: Telophase I and cytokinesis are the final steps of the first half of meiosis. A. Describe what happens when you click on the chromosomes during telophase I.

chromosomes unravel and the nuclear envelope reforms around them.

B. Click and drag on the contractile ring. Describe what happened during cytokinesis.

Structure made of actin and myosin filaments that forms a belt around a dividing cell, pinching it in two.

5. Observe: Go through the steps of the second half of meiosis until you reach the end of telophase II, following the instructions at the top right corner. As you proceed, answer the questions below. Use the Back button if you need to see a step again. A. Before prophase II begins, does the DNA in the cell duplicate itself?

no, before the prophase II begins, the DNA doesn’t cell duplicate itself.

B. During metaphase II, do homologous chromosomes pair up as in metaphase I?

no, during metphase II the homologus chromosomes don’t pair up as in metaphase I.

C. How does anaphase II differ from anaphase I?

The way the anaphase II differ from anaphase I is, anaphase I has chromosomes, anaphase II has sister chromatids.

D. At the end of anaphase II, how many chromatids are on each side of the cell?

At the end of anaphase II, 2 chromatids are on each side of the cell

E. Are all of the cells the same size?

yes, all of the cells are all the same size.

The original parent cell is called diploid because it contains a complete set of homologous chromosome pairs. Each of the four daughter cells is haploid, meaning that each contains half of the original parent cell’s chromosomes. Each daughter cell contains one chromatid from each homologous pair. 6. Observe: Click on the spermatids. Spermatids that formed from meiosis will develop into mature male gametes called sperm cells.

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Mature sperm cells have only a small amount of cytoplasm and use their flagella, or “tails,” to propel themselves forward. Sperm are designed for one purpose, to deliver genetic material to the egg cell during fertilization.

Activity B: Comparing female and male gametes

Get the Gizmo ready: ● Make sure the STEPS tab is selected. ● Click Reset.

Introduction: Although both male and female gametes contain genetic material from the parent organism, they perform different functions. A male gamete delivers genetic material to a female gamete. The fertilized female gamete, called a zygote, then grows into the offspring. Question: What are the differences in meiosis between male and female cells? 1. Compare: Click on the Female button. For the female cell, proceed through meiosis until you reach the end of anaphase I. Up to this point, did you notice any differences between the development of male and female gametes? Explain. no, I didn’t really se any major differences between the development of male and female gametes. They have the same process of the cell start growing, then the DNA condenses into chromosome and etc….. 2. Compare: Proceed through telophase I and cytokinesis I. A. What do you notice about the size of the two resulting cells?

I notice that with the size of the two resulting cells is that 3 small cells , 1 larger cell size.

B. How does this compare to the two cells at the end of telophase I and cytokinesis I in male cells?

This compares to the two cells at th of telophase I and cytokinesis I in male cells. With males it splits into 2 but with female it splits into 4.

3. Compare: Continue through meiosis until you finish telophase II and cytokinesis II. A. What do you notice about the four cells now?

I noticed that the four cells have a different outer layer than the male cells

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did. It looks kinda double layered. B. What is the largest cell called?

The largest cell is called ovum.

The ovum is the largest cell in the human body. In contrast, the sperm cell is the smallest cell in the human body.

C. What are the small cells called?

The small cells are called polar bodies.

Polar bodies are small cells that develop as a byproduct of meiosis in females. In humans and most other animals, these cells play no significant role and soon die.

4. Think and discuss: Why do you think egg cells are large and sperm cells are small? I think the egg cells are large cand the sperm cells are small because a egg cell has to be able to create a new life, while a perm cell just carries genetics.

Get the Gizmo ready:

Activity C: Genetic diversity

● Make sure the STEPS tab is selected. ● Click Reset.

Introduction: The activities above show that organisms can produce at least four different gametes. In reality, organisms can produce millions of genetically unique gametes. Question: How can meiosis create an unlimited number of unique gametes? 1. Experiment: Use the following abbreviations for the chromosomes. Dark green – DG; Light green – LG; Dark purple – DP, Light purple – LP. Choose a Male or Female cell. A. Proceed through meiosis to anaphase I. Which chromosomes went up and which went down? Up: LG&DP

Down: DP&LP

B. Click Back and run anaphase I again a few times. Did the results ever change? Explain. I didn’t notice any differences everything seemed the same when I ran it back over and over again. The chromosomes did what they were supposed to do. become atrached to the centrosome. With the LG&DP going up and DP&LP going down.

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C. Chromosomes are distributed randomly during anaphase I. What are the possible chromosome combinations in the two daughter cells? (Use DG, LG, DP, and LP.) Possible chromosome combinations in the two daughter cells could be LG,LP and DG,DP or LG,DP and DG,LP. 2. Experiment: Click Reset. Choose a Male or Female cell. Proceed through meiosis until the chromosomes are condensed in Prophase I. Drag the LG (light green) chromosome to the Allele map on the left. This shows the alleles (or variations of a gene) that are present on the chromosome. A genotype is a list of alleles. The genotype of the LG chromosome, for example, is EEFFGGHHJJ. A. What are the genotypes of the remaining chromosomes? DG:

eeffggh hjj

LP:

AABBC CDD

DP:

aabbcc dd

B. After moving the centrosomes, drag the pairs of homologous chromosomes together. Click on a chromosome. What happens?

When I click on the chromosomes, the chromosomes swapped pieces.

When homologous chromosomes are paired up, they can exchange sections. This exchange of genes is called a crossover. C. Click on several segments to create crossovers, and then click Continue. Proceed to anaphase I. Drag each chromosome to the Allele map and write its genotype. LG:

EEFFGG HHJJ

DG: eeffgghhjj

LP:

AABBCC DD

DP:

aabbccdd

3. Think and discuss: In this Gizmo, only one crossover is allowed in each segment. In reality, crossovers can occur at almost any point along the chromosome. How do the random distribution of chromosomes and crossovers create more variation in the resulting gametes? The way the random distribution of chromosomes and crossovers create more variation in the resulting gametes is different combinations of chromosomes in the resulting

gametes. Crossovers allow more random mix up the alleles that each gametes would receive creating almost unlimited numbers.

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Activity D: Crossover challenge

Get the Gizmo ready: ● Select the EXPERIMENTATION tab. ● Select the Free explore radio button.

Introduction: Earlier, you learned how crossovers can result in genetically diverse gametes. In this activity, you will perform crossovers in parent cells undergoing meiosis and combine the resulting gametes to produce offspring with specific genotypes. Question: How can offspring be created that have a specific phenotype and genotype? 1. Explore: The EXPERIMENTATION tab shows a simplified fruit fly genome, with a single pair of homologous chromosomes. Each chromosome has genes that control wing shape, body-color, antenna type, and eye color. The uppercase alleles are dominant and the lower case alleles are recessive. The allele key is given at the lower left. (Note that real fruit flies have eight chromosomes and many more genes.) A. Click Reset. Without creating any crossovers, click Divide into gametes. What are the possible genotypes of the gametes?

The possible genotypes of the gametes are a)CCBBLLRR b) ccbbllrr 1st combination: CcBbLlRr

B. Click Show phenotype for each combination. What are the resulting phenotypes?

2nd combination: cCbBlLrR 3rd combination: ccbbllrr Phenotype 1: paper wasp

C. Click Show phenotype for each combination. What are the resulting phenotypes?

Phenotype 2: golden wasp

2. Experiment: Click Reset. You can create crossovers by clicking on the middle chromatids in each of the parent cells. A. Create a gamete with the genotype C b l r. First, click on the c gene in one of the parent cells to create the crossover. Then, click Divide into gametes. Did you create a gamete with the genotype C b l r?

A. Did you create a gamete with the genotype C b l r? Yes I did.

B. Click Reset. Create a gamete with the genotype: c b L R. How many crossover were needed to create this gamete?

B. How many crossovers were needed to create this gamete? I needed 4 crossovers to create this gamete.

When a crossover occurs, the entire portion of genetic material is swapped between the two homologous chromosomes, so gene C is swapped along with gene B and gene R is swapped along with gene L.

C. How many crossovers were needed? I needed 4 crossovers.

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C. Click Reset. Create a c B L r gamete.

3. Challenge: Select the Challenge radio button. Make sure that Target offspring 1 is selected in the dropdown menu. Target offspring 1 is a fruit fly with normal wings (cc), a black body (bb), normal antenna (ll) and red eyes (Rr). Because the offspring receives one chromatid from each parent, each chromatid should come from a different parent. A. Using the Gizmo, create a fruit fly with the correct genotype. Explain how you did it.

I used the Alle key, and the hints in the description to tell me how to gentically create the bug. In the description it clearly stated which codes I needed to use. ccbbIIRr. So I could get the normal wings,black body, normal antenna and red eyes.

B. Is there another way to get the correct phenotype, but not the correct genotype? Explain.

No, because genetic code is unique to each living organism that for it to be changed even the slightest bit it wouldn’t be the same organisms with the exact 100% DNA.

4. Challenge: Use the dropdown menu to switch to the next target offspring. While creating target offspring 2- 3, fill out the table below.

CBlr

Number of crossovers Parent 1 2

Number of crossovers Parent 2 2

cblR

3

2

Target offspring

Genotype of chromatid 1

Genotype of chromatid 2

2

CBlr

3

CblR

5. Think and discuss: Suppose there are two homologous chromosomes. Each chromosome contains a single mutant allele in different parts of the chromosome. How can crossovers be beneficial in this situation? (Hint: How can you create a single, mutation-free chromosome?) Crossovers can be used in this situation by taking the two mutated alleles and combined them which would create a normal allele, in theory of course.

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